1. Field of the Invention
The present invention relates to a pipe stopper for inserting within, and sealing, a pipe, and a remote installation device for installing an expandable pipe stopper.
2. Description of the Related Art
Pipe stoppers are known which include arrangements wherein co-axial plates are moved towards each other by cam means to squeeze one or more radially expandable seals disposed between them, the stoppers being axially elongated to ensure their stable positioning in the pipe.
Stoppers are also known which include arrangements wherein co-axial plates are moved towards each other by pivotable cam means to squeeze a radially outwardly expanding seal disposed between them into contact with a bore of a pipe, an annular wear plate in the form of a plane washer being interposed between the cam means and the adjacent one of said co-axial plates. The wear plate is the disposed on an externally screw threaded spigot that is fixed to the centre of one of said co-axial plates and passes through a central aperture in the other of said co-axial plates. The cam means are pivotally mounted on a collar having an internal screw thread by which the collar is positioned on the spigot. This known arrangement has the disadvantages of the cam means when operated tend to force the co-axial plates towards each other in a non-parallel manner; and also push the wear plate sideways into engagements with the screw threads on the spigots, causing jamming of the desired squeezing action of the cam means.
Pipe stoppers may be used in locations which are not easily accessed. For example, pipe stoppers are used for stopping pipes emerging into manholes in sewers. This may require a person inserting the pipe stopper to undertake specialist confined spaces training and take specified precautions to enter the manhole and insert the pipe stopper.